Object not visible in render
In object mode press W -&gt; clear all restricted render. That will make all objects visible in the render. Also you can select and object and hit Ctrl+Alt+H to unrestrict render on the selected object. If there are objects that you have that you do not want rendered you can click the camera button next to the objects name in the outliner which is usually the top right window. This toggles camera visibility.
Version 2.80+ : Press F3 to bring in the search operator  and type clear all restrict render.